1. Field of the Invention
The present invention is directed generally to a tool holder, and more specifically, to an easy-centering cutting tool holder for interchangeably securing a tool to a machine with a cutting edge of the tool centered.
2. Description of Related Art
Conventional machines such as boring machines, threading machines, grooving machines, trepanning machines, and any other machine that must have a cutting edge of a tool secured thereto centered at a desired location relative to a workpiece are provided with a chuck for receiving the tool. In use, the machine holds the tool in contact with a piece of material referred to herein as a workpiece to remove material from the workpiece to form an end product, or a component thereof. One end of the tool is adapted to be received into the chuck of the machine while the other end is configured to support a cutting tip that will actually contact and cut material from the workpiece.
The cutting tip secured to the end of the tool has a configuration that requires the cutting tip to be centered, which means having a predetermined angular orientation within the chuck to be properly positioned relative to the workpiece. Small deviations from this centered position can result in the formation of an undesirable end product from the workpiece. Traditionally, operators have inserted the tool into the chuck at what they perceive with the naked eye to be the proper angular orientation therein. Such approximation of the tool's angular orientation is often inaccurate, requiring the operator to gradually position the tool near the workpiece and repeat the process to achieve the proper angular orientation. This is time consuming, and preoccupies the machine leading to significant periods of down time.
Previous attempts to secure the tool within a collet received within the chuck requires the tool to be properly positioned, followed by the tightening of a fastener that secures the collet within the chuck. The tool must first be properly positioned within the collet in the chuck, followed by the tightening of the fastener, which often requires rotation in a tightening direction about a central axis of the collet. This rotation of the fastener during tightening can inadvertently lead to rotation of the collet, and accordingly, the tool disposed therein. And again, when inadvertent rotation of the tool occurs, the tool's position is not centered, thereby resulting in erroneous machining of the workpiece, requiring repeated attempts to properly center the cutting edge and significant down time of the machine. Additionally, failure to properly center the cutting tip of the tool can result in premature wear of the cutting tip and possibly excessive vibrations of the tool and machine.
Conventional tool holders, once installed with the tool in the machine at the proper angular orientation, also require the operator to slowly adjust the position of the tool adjacent to the workpiece to determine the distance that the tool extends outwardly from the machine. This process, commonly referred to as “touching off” the tool to the workpiece, must be repeated each time a new tool is coupled to the machine, and the measured distance manually entered into a computer for controlling operation of the machine. Thus, only the tool currently in use by the machine can be properly configured for such use, and the touching off process must be repeated when that tool is replaced, again leading to significant down time of the machine.
Accordingly, there is a need in the art for a centering tool holder for releasably installing a tool on a machine for performing machining operations on a workpiece. The tool holder can readily center the tool to establish a predetermined angular orientation of the tool for a given machining operation, establish a known clearance between the workpiece and the tool when installed on the machine, and can optionally be compatible with a variety of tools.